شاخص هاي رشد جمعيت سنك قوزه ي پنبه و شكارگرهاي NABIS CAPSIFORMIS )HET:NABIDAE( و CHRYSOPERLA CARNEA )NEU: CHRYSOPIGLAE(

Population Growth Statistics of Creontiades pallidus (Het.: Miridae) and Associated Predators Nabis capsiformis (Het.: Nabidae) and Chrysoperla carnea (Neu.: Chrysopidae)

Creontiades pallidus Ramber is a major pest of cotton fields in some parts of Iran especially in Khorasan province. Two predators, Chrysoperla carnea (Steph.) and Nabis capsiformis Germ. as important natural enemies in cotton fields are able to reduce the population of C. pallidus. The main purpose of this study was to compare population growth statistics of both the predators and their prey to evaluate the efficiacy of C. carnea and N. capsiformis on population change of C. pallidus. Both predators and the prey were originaly collected from cotton plants and reared in laboratory. Insects rearing and all experiments were conducted in a growth chamber at 26±1ʹC, 65±5% RH and a photoperiod of 16:8 (L:D) h. Gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of natural increase (r,,,), finite rate of increase (e), mean generation time (T) and doubling time (DT) of C. pallidus were 68.48, 20.37, 0.068, 1.071, 29.37 and 10.12, respectively. However, the same parameters were estimated for C. carnea as 165.38, 133.57, 0.095, 1.10, 42.95 and 7.26, respectively, and for N. respectively. The results parameters especially r,,, C. pallidus. Our findings than N. capsiformis and population of C. pallidus. capsiformis as 95.10, 22.37, 0.037, 1.037, 48.35 and 18.63, indicated that the rate of population growth and reproduction and R0 of C. carnea were greater than N, capsiformis and suggest that C. carnea show greater efficacy on prey population thus it may be a successful biological agent for reducing the